Furnace stoker



May l5, 1934. H. E. PRESTON FURNACE STOKER Filed Feb.

l, 1950 8 Sheets-Sheet 1 May 15, 1934 H. E. PRESTON 1,958,639

FURNACE STOKER Filed Feb. l, 1930 8 Sheets-Sheet 2 l n r. n l l l n 1 n May 15, l934- I H. E. PRESTON 1,958,639

FURNACE STOKER Filed Feb. l, 1930 8 Sheets-Sheet 3 mam May 15, 1934. H. E. PREsToN FURNACE STOKE-R Filed Feb. l, 1930 8 Sheets-Sheet 4 yMay 15, 1934. H, E PRESTON 1,958,639

FURNACE STOKER Filed Feb. l, 1930 8 Sheets-Sheet 5 Z s /W 6, 999% May 15@ 1934 H, E. PRESTON f .1,958,639

FURNACE STOKER Filed Feb. 1, 1930 a sheets-sheet 6 Mm/aw H. E. PRESTON FURNACE sToKER May 15, 1934.

8 Sheets-Sheet 7 Filed Feb. l, 1930 Patented May 15, 1934 'UTED STATES 'PATENT oFFicE FURNACE STOKER Application February 1, 1930, Serial No. 425,316

29 Claims.

This invention relates to improvements in mechanical stokers of the underfeed type, and relates more particularly to improvements in the mechanism for actuating the fuel-feeding elements.

One of the objects of the invention is to provide a novel construction affording great flexibility in the individual and relative adjustments of the fuel-feeding elements.

Another object of the invention is to provide a construction rendering immediately available at the exterior of the stoker structure the devices through which said adjustments are made.

The invention further contemplates improvements in the structure of the ram and in the operating mechanism therefor. In this respect, a specific object of the invention is to provide a novel ram mechanism aording a reciprocatory movement of the ram with a minimum of componential forces angular to the normal line of movement, thereby reducing wear in the ram and load on the power mechanism.

Another object of the invention is to provide a renewable ram construction in which those parts or the ram most subject to wear are detachable and renewable from a basic ram structure including the connecting rod journal.

Another object of the invention is to provide means for balancing the pushers against the extension grate in a manner to equalize the'ellects of the horizontal forces exerted through the pusher and extension grate actuating mechanism.

A still further object of the invention is to provide means for obtaining a balanced effect in the bell crank mechanism constituting a part of the l aforesaid actuating mechanism.

Another object of the invention is to provide a novel shearing pin connection for each individual pusher rod permitting easy replacement of the latter.

The invention further resides in certain structural and operating details hereinafter set forth including a novel and improved construction of the fuel-pushing elements, all as hereinafter set forth and illustrated in the attached drawings, in which:

Figure l is a side elevation of the forward end of a Stoker made in accordance with my invention;

Fig. 2 is a side elevation of the rear end oi' the Stoker;

Fig. 3 is a fragmentary sectional view on the line 3 3, Fig. l;

Fig. 4 is a fragmentary plan view showing details of one of the rams and the immediately associated operating mechanism;

(Cl. 11G- 44) Fig. 5 is a section on the line 5 5, Fig. 4;

Fig. 6 is an enlarged fragmentary sectional View showing in side elevation details of the ram and pusher-operating mechanism;

Fig. 7 is a fragmentary sectional view illustratv60 ing details of the pusher and extension grate operating mechanism;

Fig. 8 is an enlarged fragmentary sectional view on the line 8-8, Fig. 7

Fig. 9 is a plan view of one of the pushers;

Fig. 10 is a side elevation of the pusher;

Fig. 11 is a section on the line 11-11, Fig. 9, and

Fig. 12 is a section on the line 12-12, Fig. l0.

With reference to the drawings, the front framework of the stoker consists in the present instance of a plurality of vertical beams 1 supporting a transverse horizontal composite beam 2 which in turn constitutes a support for the forward ends of rearwardly projecting brackets 3, to which are secured the ram boxes 4. The rear ends of the boxes 4 are secured to and supported upon a series of vertical beams 5, which beams also constitute the forward support for the inclined beams 6 which constitute the main supporting frames for the stoker retort structure desso ignated generally in Figs. 1 and 2 by the reference numeral '7. In the present instance, the bottoms of the retorts are composed of a plurality of fixed plates 8 and pusher elements 9 which are adapted for reciprocation between the plates 8 after a 85 manner well understood in the art and illustrated in the drawings. At the lower ends, the retorts empty upon an extension grate 11 composed of a plurality of reciprocating elements adapted for actuation with the pushers, as hereinafter set forth.

Journaled in the forward ends of the brackets 3 is a main actuating shaft 12, see Fig. 4, this shaft being provided with a series of cranks 13 which through connecting rods 14 are connected with 95 the rams l5 which operate within the boxes 4 in well known manner to discharge fuel entering the boxes through hopper openings 16 into the upper ends of the retorts. At the extreme upper ends of the retorts and immediately adjacent the mouth of the ram cylinder the sides of the retort are provided with replaceable wear plates 10.

The construction of the rams is best illustrated in Figs. 3 to 6, inclusive. As therein shown, the rams individually comprise a hollow cylindrical portion 17 which in assembly neatly and slidably fits within a cylindrical liner 18 secured in the bore of the ram box, after a manner well illustrated in Fig. 5. 'I'he ram further comprises a base member 19 comprising a substantially an- 110 Cil nular flange 21, from one face of which projects into the interior of the cylindrical portion 17 an extension 22 which includes a journal 23 for the end of the connecting rod 14, the flange 21 and the said extension 22 being longitudinally recessed as shown in Fig. 3 for reception of the rod 14, and said recesses being so formed as to provide ample clearance allowance for the angular movement of the connecting rod. As shown in Fig. 5, the extension 22 in the assembled ram fits neatly within the hollow cylinder 17, which latter seats at one end against the face of the ange 21, and the cylinder and base member are secured together by means of a screw 24, which as shown in Fig. 5 passes through the outer-'endof the cylinder 17 and is threaded into the end of the extension 22 of the base member 19. It will be noted that in this construction, aside from the -act that the cylindrical portion 17, which is subject to greatest wear, may be detached and replaced, that .thepoin't of connectionbetween the connectingrod 14 and the ram is at a point approximately 'iat ithe longitudinal center of the ram whereby the components ofthe thrust 'exerted on the ram -through the connecting rod 14 -which tend to twist the ramangularl-y with respect -to its normal line of movement in the ram cylinder are practically eliminated, thereby materially reducing Wear and also the power required for reciprocation of the :ram within the cylinder. It will further be noted `that in-detaching the cylindrical portion ,'17 of the ram, it is unnecessary to detach the connecting rod 14 at the journal, it being suffifcient to release Athe screw 24 to permit remo-val landreplacementof the'detachable part 17.

At opposite sides of the Aflange -21 are trunnions 525, 25, which are respectively rconnected by the short connecting rods 26 with 'corresponding yarms 'of 'bell-'crank levers 27, these levers being 'mounted one at Aeach side of 'each of the ram .boxes '4 upon the ends of a shaft 28 journaled .in each instance'ina bearing 29 depending from the said boxes, see Figs. 5 and v6. `The other arms 'of the 'bell-crank levers 27 are respectively connected through links 31 with the upper end of vrods 32, these rods being connected through a `series of bell 'cranks 33 and links 34 with rods connected as hereinafter setforth with the pushers 9. The rods 35 are slidably'mounted in guide brackets 36, these brackets being secured in vertical arrangement t'o the upright `beams '5, see Figs. l1 and 6. 'The 'brackets 36 are ange'd, and these flanges "37 through which the brackets are secured to vthe beams abut one another and thereby close the spaces between the said lbeams 5 to form a wall of the enclosure beneath the retorts which constitutes the air box Vof the furnace into which the draft air is forced and from which the air passes to the fuel bed through the tuyres 38. The brackets 36 vinclude extensions from both faces of the flanges 37, the inner extensions constituting -guides for the rods v35 and the outer .projecting portions forming aligned guides for cross Aheads 39, see Fig. 8, through which the rods 35 extend and to theoppositesides of which the links 34 are attached. Those portions of the rods 35 which project through the outer extensions of the brackets 36 vcarry a sleeve 41, which sleeve constitutes a sliding bearing for the cross head`39. Ihe inner end ofthe sleeve-41 is threaded and receives a nut 42, this nut vlimiting 'the relative movement of the Icross head `and the sleeve-in one direction. The other-end of the sleeve is also threaded for reception of a collar 43, which collar is xed to the extremity of the rod 35 by means of a shear pin 44.

Intermediate the cross head 39 and the collar 43, the sleeve 41 carries an outer sleeve 45, a Washer 46 abutting the outer end of this sleeve and one or a plurality of detachable substantially horse-shoe shaped elements 47, the latter constituting spacing washers which are readily detachable for adjustment purposes. The number and width of the washers 47 and the length of the sleeve determines the extent of the lost motion between the sleeve 41 and the cross head 39, 'and'assuming a given travel of the cross head 39, the stroke of the rod 35.

The-foregoing device provides a ready means `for adjusting the stroke of the rod 35 and the pushers associated therewith from the exterior `of ythe furnace, and by means of the operating connection between the cross head 39 and the shaft 12 and of the adjusting mechanism describedfabove, itwill be apparent that the stroke of "each of the rods 35 may be regulated independently of the stroke of the others. From the foregoing description and with reference to Figs. l2 and 3, it will be noted that the pushers rods 49 suspended from the ram boxes, these rods being threaded in those parts embraced by the lugs 48 for reception of nuts 51 which in sets of two are brought into engagement with the tops and bottoms of the lugs 48 to support and maintain in alignment the rear ends of the brackets 36, and to reinforce this portion of the brackets against the thrusts exerted thereon by the various operating parts including the bell cranks 33, which, as illustrated in Figs. 6 and 8, are secured to pins 52 journaled in bearings 53 in the outer ends of the brackets. At their inner ends, the brackets are formed with openings 54 including a countersunk recess 55 for reception of packing, this packing being held in place by means of a suitable gland 56, 'as shown in Fig. 8.

With reference to Figs. 1 and 8, it will be noted that .the lowermost of the bell `cranks 33 includes a third arm 57 which'connects through the medium of the link 58 with the cross head 39 of the lowermost bracket, and throughthis cross head with the lowermost of the rods 35. The uppermos't 'of the rods 35 is connected through a link `59 with the cap pusher 9. The others of the rods 35, with the exception of the bottom, are 'connected through rods 61 with the respective pushers,- the connection between the rods 61 and 35 being in each instance a liexible one by reason of a fixture 62 which is pivotally connected through a pin with the inner end of the rod 35, the lixture 62 also providing for elongating or shortening the overall length of the rods 61.

At the outer end, each of the rods 61 carries a hook 463 which engages and grips a transverse pin in the pushers. The connection between the rods 35 and the pushers is accordingly a highly flexible one, rendering adjustment and -demounting of the various elements a relatively simple one. The lowermost rod 35 is connected through a similar fixture 62 and r'od 61 l with a pivoted lever 64, the other end of which is connected through a link and a rod 66 withan element of the extension grate 11. It will be noted, therefore, that the -lowermost `of the bell cranks 33 is operatively connected both with the bottom pusher and with the extension grate 11, and further that while in this connection the lowest pusher rod 35-61 and the extension grate rod move oppositely in their normal strokes, the resultant movements of the pusher and eXtension grate are in the same direction, this by reason of the indirect connection through the lever 64 of the extension grate and its operating rod 35-61. By reason of the fact that the lower pusher rod 35-61 is always under tension when the corresponding rod of the extension grate is under compression, it will be noted that the forces acting upon the lower bell crank 33 are to a large extent balanced, which is desirable from the standpoint of durability and efliciency.

The details of the pushers 9 are shown in Figs. 9 to l2, inclusive. Each of the pushers comprises a relatively open and light base frame 68 which constitutes the main rear portion of the pusher and which has openings 69 in which the pin 63 is mounted. The frame 68 has a forward extension '71 which constitutes a support for two detachable nose piece sections 72 and 73, these sections as illustrated fitting over the extension '71 from each side thereof and overlapping along a longitudinal center line as indicated at 74 to form a substantially solid fuel-engaging nose for the pusher. The sections '72 and 73 in the present instance are corrugated or toothed at the sides as indicated at "l5, this formation in operation giving a desirable scraping action preventing accumulations of finely divided fuel within the retort. The extension 7l of the base frame 68 also has at its forward end and on the under side a transverse recess 76 for a scraper bar which operates upon the tops of the fixed plates 8. It will also be noted that each of the fixed plates 8 is provided at the tip with a resilient scraper element '77 which engages and operates upon the top surface of the pusher nose. These last named sections are secured to the pusher frame by means of bolts 78 as illustrated, the device providing a readily detachable and replaceable nose for the pushers. The scraper elements tend to prevent sifting of coal dust past the pushers.

I claim:

l. In a Stoker, an inclined grate structure including retorts, pushers in the bottoms of said retorts, a support for the elevated end of said grate structure including a plurality of spaced upright beams, a plurality of members secured to said beams in abutment with each other and forming with said beams an enclosing front wall for the space underlying said grate structure, rods connected with said pushers and guided in said members, and pusher-actuating means connecting with said rods exterior of said wall.

2. In a stcker, an inclined grate structure including retorts, pushers in the bottoms of said retorts, a support for the elevated end of said grate structure including a plurality of spaced upright beams, a plurality of members securedto said beams in abutment with each other and forming with said beams .an enclosing front Wall for the space underlying said grate structure, rods connected with said pushers and guided in said members, and pusher-actuating means connecting with said rods exterior to said wall, said connection including adjustable means for regulating. the stroke of said pushers. i

3. In a Stoker, an inclined grate structure including retorts, Vpushers in the bottoms of said retorts, a support for the elevated end of said'. grate structure including a plurality of spaced upright beams, a plurality of flanged members' secured to said beams with the said flanges in abutting relation to form a front enclosing wall for the space underlying said grate structure, pusher-actuating mechanism including pusher rods guided in said nanged members and projecting therethrough to the exterior of said wall, and an adjustable lost motion connection between the said actuating mechanism and the projecting ends of said pusher rods.

4. In a Stoker, an inclined grate structure including retorts, a front enclosing wall for the space beneath said grate structure, pushers in the bottoms of said retorts, pusher rods, guides for said rods projecting inwardly from said wall, a cross head operatively associated with each of said rods, guides for said cross heads projecting outwardly or said Wall, an adjustable lost motion connection between the cross heads and the respective rods, and pusher-actuating mechanism operatively connected with said cross heads.

5. In a Stoker, an inclined grate structure including retorts, pushers in the bottoms of said retorts, actuating rods connected with said pushers, a support for the elevated end of said grate structure, elements secured to said support in abutting relation and constituting a front-enclosingwall for the space underlying said grate structure, guides for said pusher rods, pusher-actuating mechanism, and an individually-adjustable connection between each of said rods and said mechanism exterior to said wall.

6. In a stoker, an inclined grate structure including retorts, pushers in the bottoms of said retorts, a front enclosing wall for the space underlying said grate, actuating rods connected with the pushers and extending lthrough said Wall, cross heads having an adjustable lost motion connection with the outer projecting ends of said rods, and actuating mechanism operatively associated with said cross heads.

7. In a Stoker, a-n inclined grate structure including retorts, pushers in the bottoms of said retorts, a front enclosing wall for the space underlying said grate structure, pusher-actuating rods extending through said wall, cross heads, guides for said cross heads projecting fro-m the outer face of said wall, actuating mechanism operatively associated with said cross heads, and an adjustable lost motion connection between the cross heads and said rods. t.

8. In a stoker, an inclined grate structure including retorts, a front enclosing wall for the space underlying said grate structure, pushers in the bottoms of said retorts, pusher rods extending through said front wall, relatively fixed spaced abutments associated with the outer ends of said rods, cross heads confined between said abutments, actuating mechanism operatively associated with said cross heads, and readily detachable elements adapted for mounting on said rod extensions intermediate the abutments to limit the free movement of the cross heads with respect to the rods.

9. In a stoker, the combination with a fueladvancing element, of an actuating rod for said element, a sleeve fixed tosaid rod, a cross head slidable on said sleeve, spaced abutments on said sleeve limiting the free movement of said cross head with respect to the rod, and a plurality of elements adapted for readily detachable connection with said sleeve intermediate said abutments and constituting means for regulating the extent of the free movement of said cross head with respect to the rod.

102 In a stoker, an inclined retort, a plurality of pushers arranged in vertically stepped relation in the bottom of said retort, actuating rods connected with said pushers, a plurality of guide members arranged in a vertical series, cross heads in said guides operatively connected with the respective pusher rods, a bell crank journaled in each of said rods and operatively connected with the respective cross heads, a substantially vertical rod having operative connection with all of said bell cranks, and pusheractuating mechanism with which said vertical rod isoperatively connected. f

11e. In a stoker, the combination with an inclined retort, pushers mounted in vertically stepped relation in the bottom of said retort, actuating rods-extending from said pushers, cross heads operatively associated with said rods, a vertically arranged set of guides for said cross heads, a shaft journaled adjacent each of said guides, a bell crank at each end of each of said shafts formed thereby into two vertically arranged sets at opposite sides of the guides, rods connected with the corresponding arms of the bell cranks of the respective sets, links connecting the other arms of the bell cranks with the respective cross heads, and actuating mechanism operatively associated with said crank-connecting rods.

12. In a stoker, an inclined retort, pushers mounted in the bottom of said retort, an actuating rod connected With each of said pushers, a cross head operatively associated with each of said rods, a bell crank operatively connected with each of said cross heads, and a common actuatin mechanism for said bell cranks.

13. In a stoker, an inclined retort, pushers mounted in stepped relation Within said retort, an actuating rod connected with each of said pushers, a cross head operatively associated With eachof said rods, a bell crank connected to opposite sides of each of said cross heads, a shaft connecting each associated pair of bell cranks, a pair of rods respectively connecting the bell cranks of the respective sets at opposite sides of the cross heads, a bell crank lever operatively connected with both of the last-named rods, and mechanism for actuating the bell crank last named.

14. In a stoker, a retort, a cylinder associated with said retort, and a ram operating in said cylinder -to feed fuel therefrom to the retort, said ram projecting at one end from said cylinder, ltrunnions on the projecting portion of the ram, bell crank levers, links connecting the levers with the trunnions, pushers in the bottom of said retort, mechanism operatively connecting the pushers with said bell crank levers, and mechani'sm for actuating the ram.

15. In a stoker, an inclined grate structure including retorts, pushers in the bottoms of said retorts, a front enclosing wall for the space underlying said grate, actuating rods connected with the pushers and extending through said wall, cross heads operatively connected with the outer projecting ends of said rods, said connection including a shear pin, and actuating mechanism operatively associated with said cross heads.

16. Ina stoker, a retort, an extension grate associated with said retort, a pusher in thefretort, a bell crank lever, connecting rods joining the different arms of said bell crank lever respectively with the pusher and with the extension grate, mechanism for actuating the bell crank lever to simultaneously advance one of said rods and retract the other, and a lever interposed between one of said rods and its associated extension grate to thereby effect a simultaneous movement of the pusher and the extension grate in the same direction.

17. In a stoker, an inclined grate structure including retorts, pushers in the bottoms of said retorts, a front enclosing wall for the space underlying said grate structure, pusher-actuating rods extending through said Wall, cross heads, guides for said heads projecting from the outer face of said wall, actuating mechanism operatively associated with said cross heads, and reinforcing means for the projecting ends of said guides.

18. In a stoker, a supporting frame, an inclined grate structure supported by said frame, said grate structure including retorts, pushers in the bottoms of said retorts, a front enclosing wall for the space underlying said grate structure, pusher-actuating rods extending through said wall, cross heads, guides for said cross heads projecting from the outer face of said wall, reinforcing rods secured in said frame and to each of said projecting guides, and actuating mechanism for said cross heads.

19. In a stoker, an inclined retort, spaced dead plates in the bottom of said retort, pushers slidably mounted between said dead plates, and means carried by said dead plates and by the pushers for preventing sifting of fuel between the dead plates and the pushers.

20. In a stoker, an inclined retort, spaced dead plates in the bottom of said retort, pushers slidably mounted between said dead plates, scraper elements secured to the dead plates and engaging the tops of said pushers, and a second scraper element movable with said pushers and engaging the upper surfaces of said dead plates.

21. In a stoker, an inclined retort, pushers mounted in the bottom of said retort, an actuating rod connected with each of said pushers, a cross head operatively associated with each of said rods, a bell crank operatively connected with each of said cross heads, and a common actuating member pivotally attached to said bell cranks.

22. In a stoker having a front wall, an inclined retort, pushers mounted in the bottom of said retort, an actuating rod connected with each of said pushers and extending through said wall, a bell crank for each of said rods externally of said wall and means for connecting said bell cranks with the respective rods, and means for actuating said bell cranks to longitudinally reciprocate said rods.

23. In a stoker having a front wall, an inclined retort inwardly of said wall, pushers mounted in the bottom of said retort, and an actuating rod connected with each of said pushers, said rods extending through said wall, a series of guides on the exterior of said wall, cross heads movable in said guides and operatively connected with the respective rods, and means for actuating said cross heads to longitudinally reciprocate said rods.

24. In a stoker having a front wall, an inclined retort inwardly of said wall, pushers mounted in the bottom of said retort, andan actuating rod connected with each of said pushers, said rods extending through said Wall, a series of guides on the exterior of said Wall, cross heads movable in said guides and operatively connected with the respective rods, and means including a bell crank lever connected to each of said cross heads for longitudinally reciprocating said rods.

25. In a stoker having a front Wall, an inclined retort inwardly of said Wall, pushers mounted in the bottom of said retort, an actuating rod connected with each of said pushers and extending through said Wall, a guide at the outer side of said Wall embracing the projecting end of each of said rods, a cross head slidable in each of said guides and operatively connected with the associated rod, a bell crank lever pivotally mounted at each side of each of said guides, means connecting the bell cranks of each pair to opposite sides of one of said cross heads, and an actuating rod at each side of said guides operatively connected to the adjacent bell cranks, and mechanism for reciprocating said rods to actuate the bell cranks to in turn effect a reciprocation of said cross heads.

26. In an underfeed stoker, an inclined grate structure including a retort, a substantially vertical end Wall for enclosing the space underlying said grate structure, pushers mounted in the bottom of said retort, an actuating rod connected with each of said pushers and extending through said Wall, guides for said rods supported in said Wall, a main operating mechanism, and means externally of said Wall for operatively connecting said actuating rods With said main operating mechanism.

27. In a Stoker, a retort, an extension grate associated with said retort, a pusher in the retort, a pivotal member, connecting rods operatively connected with said member, means for actuating said member to simultaneously advance one of said rods and retract the other, and mechanism operatively associated with said rods to actuate said pusher and said extension grate said mechanism including means whereby when said pivotal member is actuated simultaneous movement will be imparted to the pusher and the extension grate in the same direction.

28. In a stoker, a retort, a plurality of fuel feeding elements associated with said retort, a pivotal member, connecting rods operatively connected with said pivotal member, mechanism for actuating said member to simultaneously advance one of said rods and retract the other, and means operatively connecting each of said rods with its associated fuel feeding element, one of said means being so constructed and arranged that when said pivotal member is actuated simultaneous movement will be imparted to said fuel feeding elements in the same direction.

29. In a stolzer, a retort, a cylinder associated with said retort, and a ram operating in said cylinder to feed fuel therefrom to the retort, said ram projecting at one end from said cylinder, trunnions on the projecting portion of said ram on opposite sides of the longitudinal center line thereof, pushers in the bottom of said retort, operating mechanism for said pushers, means connecting said operating mechanism to said trunnions, and means for actuating said ram.

HERBERT E. PRESTON. 

